Many/most of Russia's energy resources are far from China, and the ______stan's are between China and the Caucasus oilfields (let's not even try to figure how far the Arctic Circle region is from China). In addition, logistics through Gansu, Qinghai, and Xinjiang Provinces would be a nightmare. China could go for eastern Siberia, but why?
BTW, since I haven't said it outright, I oppose sending US forces into Ukraine. I've seen the map and have some understanding of logistics, supply and tactical.
Siberia is oil heavy too from what I recall, just wildly under developed
